US3079272A - Method of developing an electrostatic image - Google Patents

Method of developing an electrostatic image Download PDF

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Publication number
US3079272A
US3079272A US808568A US80856859A US3079272A US 3079272 A US3079272 A US 3079272A US 808568 A US808568 A US 808568A US 80856859 A US80856859 A US 80856859A US 3079272 A US3079272 A US 3079272A
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US
United States
Prior art keywords
developer
image
composition
electrostatic
developing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US808568A
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English (en)
Inventor
Harold G Greig
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RCA Corp
Original Assignee
RCA Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to BE589923D priority Critical patent/BE589923A/xx
Application filed by RCA Corp filed Critical RCA Corp
Priority to US808568A priority patent/US3079272A/en
Priority to GB12911/60A priority patent/GB936618A/en
Priority to FR824891A priority patent/FR1254706A/fr
Priority to DER27826A priority patent/DE1158832B/de
Application granted granted Critical
Publication of US3079272A publication Critical patent/US3079272A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/06—Developing
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/12—Developers with toner particles in liquid developer mixtures
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S101/00—Printing
    • Y10S101/37—Printing employing electrostatic force

Definitions

  • electrostatic images are produced on the surface of an insulating material. Such images comprise a pattern of electrostatic charges on the surface. Visible images are commonly produced therefrom by cascading across the surface a dry mixture f finely-divided developer particles and substantially larger carrier particles. When the developer particles are triboelectrically-charged in the opposite polarity to the electrostatic charges they deposit in charged areas to produce a visible image in substantial configuration with the pattern of charges. When the developer particles have the same polarity as the electrostatic charges a visible image is produced in reverse configuration with respect to the pattern of charges.
  • the recording element may comprise almost any insulating surface but, preferably, the recording surface is also photoconductive to enable the recording ot light images.
  • Recording elements comprising photoconductive selenium coated plates are described in US. Patent 2,297,- 691, issued October 6, 1942, to C. F. Carlson. Recording elements comprising photoconductive coatings on paper are described the Young and Greig publication, op. cit.
  • liquid developer previously described consists of timely-divided developer particles dispersed in a hydrocarbon liquid. This developer can be ilowed over a surface bearing an electrostatic image, or the surface can be immersed in a tray of liquid developer. lt can also be sprayed or rolled on to the surface.
  • appropriate developer particles are dispersed in a properly selected liquid, they acquire an electrophoretic or triboelectric charge enabling them to be attracted to an electrostatic charge pattern of appropriate polarity.
  • Depositon of the developer particles on the charge image is an example of the phenomenon known as electrophoresis or cataphoresis.
  • a liquid developer process for charge images is described in greater detail by l. A. Metcalf and R. l. lli/right in a paper entitled Xerography, published in the Journal of the Oil and Colour Chemists Association, November 1956, vol. 39, No. ll, London, England, and in another paper entitled Liquid Developers for Xerography published in the Journal of Scientic instruments, February 1955, vol. 32.
  • hydrocarbon liquids are solvents for developer powders which include resins, waxes, or organic pigments.
  • resinous particles When resinous particles are dispersed in a hydrocarbon liquid they dissolve to some extent so that they become tacky and tend to agglomerate. rihus, dispersions must be freshly made a short time prior to use. If the dispersions stand for any extended period of time, the developer particles will ball up or cake. The tackiness of the developer particles caused by the hydrocarbon liquid can also make them adhere in unwanted image areas, which they may contact during development. Also, unless the image developed with such a dispersion is fixed in some manner, the tacky developer particles will tend to smear during handling.
  • Fixing may be accomplished with a iixative spray or by heating.
  • heating can be extremely dangerous in view of the fire hazard involved. ln addition to this, whether heated or not, most hydrocarbon liquids have an objectionable odor and the vapors thereof are generally toxic. For the foregoing reasons it can be readily seen that such liquids are unsuitable for many applications such as, for example, ofce copiers.
  • Another object of this invention is to provide an improved composition of matter for deve.oping an electrostatic image, which composition minimizes tire hazard.
  • lt is a further object of this invention to provide an improved composition of matter for developing electrostatic images wherein the image produced requires no xing.
  • lt is yet another object of this invention to provide methods of developing electrostatic images which obviate the need for any tlxing or glossing steps.
  • the foregoing objects and other advantages are accomplished in accordance with this invention which provides an improved composition for developing electrostatic images, which composition is ordinarily a solid but which is heated and applied to the electrostatic image in liquid form to result in a tlxed developed visible image.
  • the composition comprises a mixture of (l) a low-melting carrier material which upon heating becomes quite iluid and which is electrically-insulating in character; (2) a dispersed phase in the carrier material of a finely-divided developer substance.
  • the low-melting material is selected to have a melting point of between about 50 C. and about 296 C. and a viscosity not in excess of about 400 centipoises at a temperature Within that range.
  • the developer substance may comprise liquid droplets or solids but should be substantially insoluble in the carrier material and when dispersed therein must have an electrical character such that, when dispersed in the carrier material, it takes on an electrical charge.
  • Also contemplated in this invention is a method of developing electrostatic images employing the aforementioned composition.
  • This method contemplates the steps of providing the above-mentioned developer composition, heating at least a portion of that composition to at least its melting point and contacting said melted portion across the electrostatic image to produce thereon a visible image of developer particles.
  • the image so produced is automatically fixed and in most cases can, if desired, present a gloss surface.
  • FIGURE 1 is a schematic, perspective view illustrating a developing method in accordance with this invention using a heated doctor blade;
  • FiGURE 2 is a schematic perspective view illustrating another developing method in accordance with this invention using a heated roller.
  • FIGURE 3 is a schematic perspective view illustrating yet another developing method in accordance with this invention using a heated roller to develop an electrostatic image with developer composition picked up from a solid strip thereof near one edge of an insulating surface bearing the electrostatic image.
  • the ratio of developer particles to carrier material in the developer composition may vary considerably. This ratio will depend to a large extent on the viscosity of the carrier material, the amount of charge taken on by the particles dispersed in the carrier material, particle size, and the density of the developer particle material.
  • Many low-melting materials may be substituted for the paraffin carrier specifically mentioned in Example I. These materials may be used either alone or in combination. Some suitable materials include:
  • Ultracera amber wax, melting point about 90 to 94 C. (a micro'crystalline petroleum wax of the Bareco l Oil Co., Barnsdall, Oklahoma).
  • Polymekon wax melting point about 90 to 93 C. (a commercially modified microcrystalline wax, Warwick Wax Co., New York, N.Y.).
  • suitable additives such as plasticizers, elasticizers, toughening agents, and dispersing agents may be employed.
  • suitable additives may include:
  • Piccolyte S-135 (a thermoplastic hydrocarbon terpene resin, Pennsylvania Industrial Chemical Co., Clairton, Pa). When added in quantities, for example, of from 6% to 8% by weight to one of the foregoing developer compositions, the Piccolyte S-135 improvesv the durability of the developed image and substantiallyl lessens the waxy texture thereof.
  • Aroclor (various mixtures of chlorinated biphenyls and polyphenyls, Monsanto Chemical Co., St. Louis, Mo).
  • the Aroclor functions as a plasticizer, toughener, hardener, and improves surface texture of the developed image.
  • Stearic acid when added to the developer compositions in amounts, for example, of from 4% to 5% by weight, improves the triboelectric charge relationship lbetween the developer particles and the low-melt material o-f the composition to thereby facilitate the electrostatic attraction of the developer particles to an electrostatic image.
  • Polyethylene (melting point about 115 C. to C.), when included in the developer composition in amounts, for example, of from 12% to 50% by weight, improvesuidity of the melted composition and provides a developed image having improved flexibility, and adhesion.
  • the foregoing and other additives or modifiers may be employed alone or in combination to alter ⁇ the electrical characteristics of the developer composition, or to alter the surface texture or flexibility of the developed image.
  • a developed image can be produced which has a high degree of flexibility, toughness and gloss; When such an image is produced on paper it will neither peel nor chip from the paper when tiexed.
  • Developer particles to be dispersed in the foregoing carrier materials may include any pigments or dyes or combinations thereof which are insoluble in the carrier material. Among these are the following:
  • these pigments may be dispersed in the carrier materials in'amounts of up to about 10% by weight of the composition, the smaller the particle size the less the amount of pigment (by weight) that is included in the composition.
  • All the foregoing developer compositions may be described as being direct printing for electrostatic images which comprise patterns ofl negative electrostatic charges.
  • developer particles when melted and applied to the Velectrostatic image, developer particles will be attracted to and deposit on those areas which bear negative electrostatic charges.
  • l This may be accomplished by applying the developer composition to the electrostatic image with a metallic applicator and electrically biasing the applicator, and hence the developer composition, during the time it is applied tothe electrostatic image.
  • a negative bias is applied to such a composition, developer particles will deposit in the uncharged areas of the electrostatic image thereby producing a -visible image in reverse configuration with respect .to the electrostatic image.
  • Color developer compositions may be prepared in a like manner and may comprise a mixture such as the following:
  • EXAMPLE III 11 to 14 grams Vinylite VNYV 2 grams pigment or dye grams dimethyl polysiloxane This composition is dispersed in a carrier material in a concentration of up to about 20% by weight of the composition.
  • suitable pigments include:
  • Example li Pyrazolone pigment (Red) (Color Index No. 21080) (2) Hansa Yellow G (3) Patent Blue (Color index No. 672)
  • the foregoing composition of Example li may also be employed to produce reverse visible images when the electrostatic image comprises a pattern of negative electrostatic charges. When the composition is applied to such an electrostatic image, developer particles will de posit on those areas of the image which bear no electrostatic charge.
  • the methods of this invention pro-vides many techniques for producing visible images from electrostatic images on an insulating surface.
  • the electrostatic image can be developed by contact with a heated surface carrying a thin film of molten developer composition.
  • This heated surface may, as illustrated in FIG. 1 for example, comprise a doctor blade.
  • the doctor blade may be biased to provide a reverse image or it may be biased to place ground close to the electrostatic image in which case it aids in filling in solid color areas.
  • an electrostatic image may be developed by passing the surface on which it resides by and in contact with a heated roller carrying molt-en developer composition.
  • the heated roller may again be biased to improve development or to provide a reversal print.
  • the developer composition may be applied in the form of a solid caire, to a surface bearing an electrostatic image. ln such a case the surface is heated to the melting point of the developer material and the solid caire is quickly passed over the surface to provide the developer image. in this instance, a developer composition having a melting point of about 60 C. or less is preferred in order that the electrostatic image not be dissipated by heat.
  • lt is also possible to provide a developer composition in the form of a solid cake to be employed in conjunction with a heated roller as illustrated in FIG. 2.
  • a heated roller will readily pick up a film of melted developer composition from the solid cake by contact and, by rotating, transfer the molten composition to the surface on which the electrostatic image rests.
  • the roller may be rolled across the surface or, in the alternative, may be caused to spin at a higher rate than that required for rolling. In the latter case, only the molten composition on the roller is in contact with the surface.
  • another technique particularly suitable for developing electrostatic images on photoconductive paper, contemplates employing a sheet of such paper which has a thin strip of solid developer composition along one edge of the photoconductive surface. Once the electrostatic image is produced on that surface, it is easily and quickly developed by contacting a hot roller to the strip of developer composition and rolling it across the surface.
  • Yet another technique comprises coating a member such as, for example, a sheet of paper or metal with the developer composition. This member is then superimposed on a surface bearing an electrostatic image, the coating on the member being in contact with the image bearing surface. The member is then heated to melt the developer composition whereupon a developed image is produced on the surface. Heating of the member may be conveniently accomplished by contacting a hot roller or other metallic member to the baci: of the member.
  • the methods of this invention also provide a unique technique for producing photographic transparencies.
  • a thin transparent insulating sheet such as, for example, a sheet of one-half Mylar is superimposed on an insulating surface bearing an electrostatic image.
  • Mylar is a polyester film; condensation product of ethylene glycol and terephthalic acid, E. l. du Pont de Nemours and Co., Wilmington, Delaware. ⁇ 'vhen this is done, another electrostatic image (as a result of induction) will appear on the exposed surface of the insulating sheet.
  • the image appearing on the insulating sheet can then be developed by any of the techniques described heretofore.
  • An unusual and surprising feature of this invention is the development of electrostatic images with developer compositions heated to temperatures of from 50 to 200 C. It is well known that elevated temperatures will dissipate electrostatic charges on any insulating surface. The dissipation of charges by heat is especially rapid with respect to electrostatic images produced on photoconductive surfaces.
  • the photoconductive coatings described in the Young and Greig publication, op. cit can retain an electrostatic image at ordinary room temperatures for at least 50 minutes. The time during which such a coating can retain an image rapidly decreases with increasing temperature until at about 60 C. or above the charge storage time amounts to only a matter of a few seconds. Thus, employing temperatures ranging up to 200 C.
  • a method of developing an electrostatic image on an insulating surface comprising the steps of: providing a solid body of developer material comprising finely-divided electroscopic developer particles dispersed in an electrically-insulating thermoplastic carrier material having a melting point substantially within a range of from 50 C. to 200 C.; heating said solid body to melt at least a portion thereof; and contacting said molten portion across said insulating surface to produce thereon a visible image of said developer particles.
  • A.method 0f developing an electrostatic image on a photoconductive surface comprising the steps of providing a solid body of developer material comprising nelydivided electroscopic developer particles dispersed in an electrically-insulating thermoplastic carrier material having a melting point within a range of from 50 C. to 70 C.; heating said surface to a temperature Withinsaid range and simultaneously and rapidly contacting said solid body across said surface thereby melting a portion of said solid body and producing on said surface a visible image of said developer particles.
  • a method of developing an electrostatic image on an insulating surface comprising the steps of: providing a member having a surface coated with a solid composition of developer material comprising finely-divided electroscopic developer particles dispersed in an electricallyinsulating thermoplastic carrier material having a melting point substantially within a range of from 50 C. t0 200 C., contacting said coated surface to said insulating surface and, while so contacting, applying heat to said coating to melt said thermoplastic material vto produce on said insulating surface a visible image of said developer particles.
  • a method of electrostatic printing comprising the steps of: providing an insulating surface having along one edge thereof a solidV strip ofA developer material having a melting point substantially within a range of from 50 C. to 200 C., comprising 'finely-divided developer particles dispersed in an electrically-insulating thermoplastic carrier material; producing an electrostatic image on another portion of said surface and applying a roller heated to a temperature Within said range to said strip of developer material and then rolling said roller across saidV surface to develop said electrostatic, image.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Developing Agents For Electrophotography (AREA)
  • Liquid Developers In Electrophotography (AREA)
US808568A 1959-04-24 1959-04-24 Method of developing an electrostatic image Expired - Lifetime US3079272A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BE589923D BE589923A (hr) 1959-04-24
US808568A US3079272A (en) 1959-04-24 1959-04-24 Method of developing an electrostatic image
GB12911/60A GB936618A (en) 1959-04-24 1960-04-11 Improvements in the development of electrostatic images
FR824891A FR1254706A (fr) 1959-04-24 1960-04-21 Impression électrostatique
DER27826A DE1158832B (de) 1959-04-24 1960-04-25 Entwickler fuer die elektrostatische Herstellung von Bildern und Verfahren zur Entwicklung elektrostatischer Ladungsbilder

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Application Number Priority Date Filing Date Title
US808568A US3079272A (en) 1959-04-24 1959-04-24 Method of developing an electrostatic image

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US3079272A true US3079272A (en) 1963-02-26

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BE (1) BE589923A (hr)
DE (1) DE1158832B (hr)
GB (1) GB936618A (hr)

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3247007A (en) * 1960-09-06 1966-04-19 Method of developing latent electro- static images ushng solid developer body and related solvent
US3272644A (en) * 1963-07-31 1966-09-13 Dennison Mfg Co Development of latent electrostatic images with crystalline toners
US3345293A (en) * 1963-09-03 1967-10-03 Xerox Corp Colored electrostatographic toners containing organic dye pigments
US3345172A (en) * 1964-12-01 1967-10-03 Polaroid Corp Photographic processing method utilizing frozen aqueous solutions
US3372027A (en) * 1964-05-15 1968-03-05 Xerox Corp Xerographic liquid development
US3372049A (en) * 1961-10-09 1968-03-05 Minnesota Mining & Mfg Polyolefin film composition, film, and pressure-sensitive adhesive sheet material
US3431890A (en) * 1967-09-28 1969-03-11 Rca Corp Apparatus for replenishing developer in an electrophotographic system
US3462285A (en) * 1964-11-02 1969-08-19 Phillips Petroleum Co Electromagnetic fusion of thermoplastic printing
US3665856A (en) * 1970-02-24 1972-05-30 Heller William C Jun Printing method using electric through-field to indelibly lodge particles
US3853554A (en) * 1971-07-24 1974-12-10 Canon Kk Process for liquid development of electronic photography
US3971659A (en) * 1968-12-28 1976-07-27 Xerox Corporation Color electrophotographic process using photoconductive particles in liquid developer
US4183818A (en) * 1968-12-28 1980-01-15 Xerox Corporation Color electrophotographic liquid developer of colored particles and zinc oxide
US4304985A (en) * 1980-05-27 1981-12-08 The United States Of America As Represented By The Secretary Of The Navy Developer for dry silver paper
US4363863A (en) * 1979-12-13 1982-12-14 Nashua Corporation Liquid negative developer compositions for electrostatic copying containing polymeric charge control agent
US4374918A (en) * 1981-09-16 1983-02-22 Nashua Corporation Thermally stable liquid negative developer
US4792860A (en) * 1987-02-27 1988-12-20 Kuehrle Manfred R Thermodynamic printing method and means
US4891286A (en) * 1988-11-21 1990-01-02 Am International, Inc. Methods of using liquid tower dispersions having enhanced colored particle mobility
EP0382142A2 (en) * 1989-02-06 1990-08-16 Sony Corporation Material for forming image
EP0433012A2 (en) * 1989-12-14 1991-06-19 Sony Corporation Developer cartridges
US5406314A (en) * 1991-11-15 1995-04-11 Kuehnle; Manfred R. Electrothermal printing ink with monodispersed synthetic pigment particles and method and apparatus for electronic printing therewith
US5783350A (en) * 1995-12-14 1998-07-21 Fuji Xerox Co., Ltd. Developer for electrostatic photography and image forming method
US11492495B2 (en) 2018-03-22 2022-11-08 3M Innovative Properties Company Modified aluminum nitride particles and methods of making the same
US11820844B2 (en) 2018-03-22 2023-11-21 3M Innovative Properties Company Charge-modified particles and methods of making the same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE594907A (hr) * 1959-09-09

Citations (12)

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Publication number Priority date Publication date Assignee Title
US1122473A (en) * 1912-04-18 1914-12-29 Thomas T Butler Process and means for coating paper with carbon.
US2297691A (en) * 1939-04-04 1942-10-06 Chester F Carlson Electrophotography
US2618551A (en) * 1948-10-20 1952-11-18 Haloid Co Developer for electrostatic images
US2735784A (en) * 1953-07-30 1956-02-21 Process of electrostatic printing
US2788288A (en) * 1953-07-29 1957-04-09 Haloid Co Process and composition for developing an electrostatic image
US2860048A (en) * 1955-06-13 1958-11-11 Haloid Xerox Inc Xerographic plate
US2886464A (en) * 1955-08-09 1959-05-12 Haloid Xerox Inc Contact transfer for xerography
US2891911A (en) * 1955-06-06 1959-06-23 Gen Dynamics Corp Developer for electrostatic printing
US2892794A (en) * 1955-01-03 1959-06-30 Haloid Xerox Inc Electrostatic developer and toner
US2917460A (en) * 1955-06-17 1959-12-15 Ibm Powder compositions useful as electroscopic toners
US2940934A (en) * 1953-06-22 1960-06-14 Haloid Xerox Inc Electrostatic developer composition and method therefor
US2974632A (en) * 1958-04-23 1961-03-14 Century Geophysical Corp Apparatus for developing electrostatic image

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1122473A (en) * 1912-04-18 1914-12-29 Thomas T Butler Process and means for coating paper with carbon.
US2297691A (en) * 1939-04-04 1942-10-06 Chester F Carlson Electrophotography
US2618551A (en) * 1948-10-20 1952-11-18 Haloid Co Developer for electrostatic images
US2940934A (en) * 1953-06-22 1960-06-14 Haloid Xerox Inc Electrostatic developer composition and method therefor
US2788288A (en) * 1953-07-29 1957-04-09 Haloid Co Process and composition for developing an electrostatic image
US2735784A (en) * 1953-07-30 1956-02-21 Process of electrostatic printing
US2892794A (en) * 1955-01-03 1959-06-30 Haloid Xerox Inc Electrostatic developer and toner
US2891911A (en) * 1955-06-06 1959-06-23 Gen Dynamics Corp Developer for electrostatic printing
US2860048A (en) * 1955-06-13 1958-11-11 Haloid Xerox Inc Xerographic plate
US2917460A (en) * 1955-06-17 1959-12-15 Ibm Powder compositions useful as electroscopic toners
US2886464A (en) * 1955-08-09 1959-05-12 Haloid Xerox Inc Contact transfer for xerography
US2974632A (en) * 1958-04-23 1961-03-14 Century Geophysical Corp Apparatus for developing electrostatic image

Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3247007A (en) * 1960-09-06 1966-04-19 Method of developing latent electro- static images ushng solid developer body and related solvent
US3372049A (en) * 1961-10-09 1968-03-05 Minnesota Mining & Mfg Polyolefin film composition, film, and pressure-sensitive adhesive sheet material
US3272644A (en) * 1963-07-31 1966-09-13 Dennison Mfg Co Development of latent electrostatic images with crystalline toners
US3345293A (en) * 1963-09-03 1967-10-03 Xerox Corp Colored electrostatographic toners containing organic dye pigments
US3372027A (en) * 1964-05-15 1968-03-05 Xerox Corp Xerographic liquid development
US3462285A (en) * 1964-11-02 1969-08-19 Phillips Petroleum Co Electromagnetic fusion of thermoplastic printing
US3345172A (en) * 1964-12-01 1967-10-03 Polaroid Corp Photographic processing method utilizing frozen aqueous solutions
US3431890A (en) * 1967-09-28 1969-03-11 Rca Corp Apparatus for replenishing developer in an electrophotographic system
US3971659A (en) * 1968-12-28 1976-07-27 Xerox Corporation Color electrophotographic process using photoconductive particles in liquid developer
US4183818A (en) * 1968-12-28 1980-01-15 Xerox Corporation Color electrophotographic liquid developer of colored particles and zinc oxide
US3665856A (en) * 1970-02-24 1972-05-30 Heller William C Jun Printing method using electric through-field to indelibly lodge particles
US3853554A (en) * 1971-07-24 1974-12-10 Canon Kk Process for liquid development of electronic photography
US4363863A (en) * 1979-12-13 1982-12-14 Nashua Corporation Liquid negative developer compositions for electrostatic copying containing polymeric charge control agent
US4304985A (en) * 1980-05-27 1981-12-08 The United States Of America As Represented By The Secretary Of The Navy Developer for dry silver paper
US4374918A (en) * 1981-09-16 1983-02-22 Nashua Corporation Thermally stable liquid negative developer
US4792860A (en) * 1987-02-27 1988-12-20 Kuehrle Manfred R Thermodynamic printing method and means
EP0295364A2 (en) * 1987-02-27 1988-12-21 Manfred R. Kuehnle Thermodynamic printing method and means
EP0295364A3 (en) * 1987-02-27 1990-06-13 Manfred R. Kuehnle Thermodynamic printing method and means
US4891286A (en) * 1988-11-21 1990-01-02 Am International, Inc. Methods of using liquid tower dispersions having enhanced colored particle mobility
EP0382142A3 (en) * 1989-02-06 1991-10-23 Sony Corporation Material for forming image
EP0382142A2 (en) * 1989-02-06 1990-08-16 Sony Corporation Material for forming image
EP0433012A2 (en) * 1989-12-14 1991-06-19 Sony Corporation Developer cartridges
EP0433012A3 (en) * 1989-12-14 1991-10-30 Sony Corporation Developer cartridges
US5075735A (en) * 1989-12-14 1991-12-24 Sony Corporation Electrophotographic apparatus using developer that is changed from a solid to a liquid
US5406314A (en) * 1991-11-15 1995-04-11 Kuehnle; Manfred R. Electrothermal printing ink with monodispersed synthetic pigment particles and method and apparatus for electronic printing therewith
US5783350A (en) * 1995-12-14 1998-07-21 Fuji Xerox Co., Ltd. Developer for electrostatic photography and image forming method
US11492495B2 (en) 2018-03-22 2022-11-08 3M Innovative Properties Company Modified aluminum nitride particles and methods of making the same
US11820844B2 (en) 2018-03-22 2023-11-21 3M Innovative Properties Company Charge-modified particles and methods of making the same

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DE1158832B (de) 1963-12-05
BE589923A (hr)
GB936618A (en) 1963-09-11

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